I am using official MCP SDK. According to official guide, Servers MUST provide structured results that conform to this schema. https://modelcontextprotocol.io/specification/draft/server/tools#output-schema I could see output schema defined, but result have no structured content. Current output schema: { name: "XcodeListWindows", title: "List Windows", description: "Lists the current Xcode windows and their workspace information", inputSchema: { type: "object", properties: { }, required: [ ], }, outputSchema: { type: "object", properties: { message: { description: "Description of all open Xcode windows", type: "string", }, }, required: [ "message", ], }, } Current response: { "result": { "content": [ { type: "text", text: "{\"message\":\"* tabIdentifier: windowtab1, workspacePath: \\xxx\\n* tabIdentifier: windowtab2, workspacePath: \\xxx\\n\"}", }, ] } } Expected: { "result": { "content": [ { type: "text", text: "{\"message\":\"* tabIdentifier: windowtab1, workspacePath: \\xxx\\n* tabIdentifier: windowtab2, workspacePath: \\xxx\\n\"}", }, ], "structuredContent": { "message": "* tabIdentifier: windowtab1, workspacePath: \\xxx\\n* tabIdentifier: windowtab2, workspacePath: \\xxx\\n", } } }